Questions by Children and Teachers.

by Mark Deprest
Printed in Reflections: October, 1998.

Each year for the past four years I have taken my telescopes and accessories
to my daughter’s school and give a small presentation to the kids in her
class. The last two years I have also been invited to be part of
the school’s science day. During their science day, they have parents
and friends who are somehow
involved in a particular science, such as astronomy, medicine, telecommunications,
etc., come in an give a small presentation to a couple of classrooms.
I am looking forward to participating this year again in the early part
of November.

I am always amazed at the questions that are posed by the children and
teachers. Some of these questions are pretty easy to answer, but
every once in while someone will ask a question that has me look just a
little deeper to find the answer. Here is a sampling of those research
provoking questions and the answers.

Q: Has anyone ever been hit by a meteor?

A: Yes! On October 9, 1992, a meteorite slammed into a parked
car, then owned by Michelle Knapp in Peekskill, New York. The car
was a 1980 Chevy Malibu and the meteorite was about 27 pounder. According
to SKY & TELESCOPE (January 1954), Mrs. Hewlett Hodges of Sylocuga,
Alabama, was struck in the hip on November 30, 1953, by a meteorite the
crashed through her living room ceiling.

Q: Is it true the Moon is moving away from the Earth?

A: Yes! This has been confirmed by more that a decade of lunar
ranging experiments using the laser retroreflectors left on the Moon by
Apollo astronauts. The rate works out to be about 3.8 centimeters
per year, and fossil sediment layering records show that this motion has
been constant for more than 900 million years at the same rate.

Q: Which Planet is hotter, Mercury or Venus?

A: Venus, at a surface temperature of 900 degrees Fahrenheit.
This is a result of the greenhouse effect trapping most of the infrared
energy and not allowing it to escape back into space. Because Mercury
has no such atmosphere at high noon it only gets up to about 800 degrees,
but that temperature drops very quickly the moment night falls.

Q: Why do the planets orbit the Sun in the same line (plane)?

A: This is a reflection of the way in which the cloud that collapsed
to form our Sun was rotating. According to computer models of such
collapsing, rotating clouds, they show that they rapidly form into a flattened
disk. The planets then formed out of this disk of heavier materials
and gasses and will orbit the star in the same plane as the original disk.

Q: Why doesn’t Mercury and Venus have moons of their own?

A: Because they are too close to the Sun. Any moon with too
great a distance from these planets would be in an unstable orbit and would
be captured by the Sun. If they were too close to these planets,
they would be destroyed by the tidal gravitational forces. The zones
around these planets where a moon could exist is very small and no body
was ever captured into orbit or was formed there when the planets were
first being formed.

Q: What do you know about the North Star?

A: It is also called Alpha Ursa Minoris and Polaris. It is
a +1.99 magnitude star that is classified as a F8 Ib star, which means
it is a very luminous supergiant with an orange-yellow color and a surface
temperature near 4000 Kelvin. It is currently about 54 arc minutes
from the true north celestial pole, and by the year 2100, it will be less
than 28 arc minutes from true north. Polaris is a double star, and
its companion is about 18 arc seconds distant from our point of view.
Its companion has an orbit of over 2000 years. Polaris is moving
through space at a speed of about 20 kilometers per second and is about
360 light years away. It has a luminosity of 1600 times that of the
sun and it may be a variable with a change in its brightness of about 0.01
magnitudes over a period of 3.9 days. There is also an unseen companion
star to Polaris that has an orbital period of about 30 years.

These are just some of the question I get asked by second, third and fourth
graders. My daughter is in fifth grade this year and I have asked
the principal not to have a talk with them on science day, because I know
I won’t survive the questions there.